Why is it that handicap games are so scarce on OGS?

[espoojaram]

@snakesss

When you can give someone 3 stones one week and take 3 stones from the same person next week, that should cause some damage to the integrity of the results of the handicap games, regardless of the results of even games, which makes me question how OGS approximates 50% winrate for strong/weak sides in handi games with such a deficit in place.

(emphasis mine ^)

I believe I might have a good conjecture to answer that, which is two-fold:

1. This is part of how statistics works: if someone’s rank oscillates a lot, they should find harder handicap games when their rank is high and easier handicap games when their rank is low; but it might just be the case that on average the games they win in excess cancel out with the games they lose in excess, leading to an overall 50% winrate. This does seem to imply that the rank oscillation somehow succeeds in being unbiased in this sense, i.e. it doesn’t systematically over-rank or under-rank players, though statistics is complicated so who knows.

2. It might also/alternatively be that the rank fluctuations manage to capture the players’ ability even more accurately and precisely than we think, down to “this player is having a good day so their rank rises” etc. – and if you think about it, if a player is having a good day it also stands to reason that they have a better chance of winning a harder handicap game than usual. So players that play a lot and see their rank fluctuate a lot might actually be the ones for which the rank is most accurate, down to their daily mood.

(This just made me think that perhaps a more “ideal” system would keep the rating as is and use it for matching and automatic handicaps, but the displayed rank [the one next to someone’s username] should be a more stable and averaged out version; but I guess that’s a bit off-topic – also it might be a bit of a PR nightmare for the devs)